Method of handling service connections in a communication network

ABSTRACT

A method for controlling connections in a communication network including setting up a signaling connection between a subscriber of the communication network and a service access system based on a service connection request by the subscriber; and setting up a payload connection associated with the signaling connection only between the service access system and the subscriber given data traffic for the service and clearing down the payload connection after the data transmission.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a communication network and the handling ofservice connections in the communication network including an Internetaccess system and a switching center.

2. Description of Related Art

A strong growth of the traffic volume in the access area to servicesthat are offered by other networks, for example the Internet, isconnected with the strong growth of Internet services and other specialservices. As a result, there is a substantial increase in the demandsmade of the exchanges forming the access area to these networks.

The situation is additionally intensified in that current exchanges arenot dimensioned for the absolute call lengths and distributions of calllengths that mainly occur in the Internet traffic, to the entry nodes ofthe Internet service providers. Even when there is a slight increase inInternet traffic volume, additional exertions of the Internet accessservice operators are needed for expanding the capacity of theirswitching centers in order to maintain the actual voice traffic with therequired quality features.

SUMMARY OF THE INVENTION

The invention is based on the object of placing network operators in theposition of governing the increasing access traffic to the entry nodesfor special services, particularly for example Internet services,without an involved expansion of the switching centers.

The object is achieved by to a method and system for controllingconnections in a communication network that includes setting up asignaling connection between a subscriber of the communication networkand a service access system based on a service connection request by thesubscriber and setting up a payload connection associated with thesignaling connection between the service access system and thesubscriber only given data traffic for a service and clearing down thepayload connection after the data transmission.

Another object of the invention provides a service that is a voiceservice and/or a data service.

A further object of the invention provides charging a service by thecommunication network for a time interval in which the signalingconnection and the payload connection simultaneously exist for theservice.

Another object of the invention provides a method in which the step ofclearing down the payload connection does not occur immediately afterthe end of data transmission but occurs immediately before theexpiration of the time interval already charged.

As object is achieved by the subject matters of claim 1 or 5.

It is already known (see e.g., Jay Tao et al., “Internet Access viaBaseband and Broadband ISDN Gateways”, Proceedings of the ThirteenthAnnual International Phoenix Conference on Computers and Communications,12-15 Apr. 1994, Phoenix, USA, pages 485-490) to check in an Internetaccess system connected to a switching center to see when an Internetconnection is closed in order to subsequently initiate the cleardown ofthe (dialed) connection previously set up for the Internet connection assoon as possible. What is thereby proposed as an especially simpleversion of monitoring is a time-monitoring that monitors the Internetconnection for inactivity. The time span monitored for inactivity,however, dare not be selected too short since the problem otherwiseoccurs that the (dialed) connection is cleared down even though the TCPconnection was not yet closed.

Up to now, a dialed connection that was once set up was maintainedduring the entire duration of the connection to a special servicesprovider in such a way that a payload channel is also occupied even inphases of the connection without data transmission. As a results, theabove-described disadvantages arise for the operators of the switchingcenters, since current switching centers are not dimensioned for theabsolute call lengths and call length distributions that mainly occur,in the Internet traffic to the entry nodes of the Internet serviceproviders.

As a result of the inventive method, the load of the switching centersby special services access traffic is limited. To this end, theswitching centers need not be dimensioned larger and/or expanded by therespective operator.

A further advantage of the invention is that the method providesdesignational control of the usage charges arising for the subscribersin the access network.

A further advantage of the invention includes offering features by theswitching center in the data transmission pauses over what are then thefree payload channels and/or over the still-occupied payload channelafter the end of the burst-like data transmission in the time availableup to the end of the time interval that has already been charged.

An exemplary embodiment of the invention is explained in greater detailbelow on the basis of the drawings.

DETAILED DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of a switching center that links theaccess network to the Internet.

FIG. 2 shows three graphs illustrating the D-channel traffic, B-channeloccupation and Internet traffic verses time.

FIG. 3A is a block diagram of a communication network incorporatingprinciples of the invention.

FIG. 3B is a block diagram of a communication network incorporatingprinciples of the invention.

FIG. 3C is a block diagram of a communication network incorporatingprinciples of the invention.

FIG. 4 is a schematic diagram of the processing by the software of theswitching center.

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS

FIG. 1 shows an entry node, i.e., a switching center that links theaccess network to the Internet. The switching center contains, forexample, a switching system of Siemens AG, namely the switching systemEWSD 10. Said switching system is expanded by an Internet line/trunkgroup LTG-I 20 that can also contain POP functions in the illustratedcase (POP server=point of presence server), but that comprises theinterface to the POP server (for example, work station computer of theSun company) in any case, whereby the POP server in turn comprises thePDH/SDH interfaces to the Internet. The terminal equipment CPE 50 a-50 g(referred to as customer premises equipment in English) that areconnected to the switching center are thus connected to a switchingcenter in the example of FIG. 1 that already represents the entry nodeinto the Internet.

Due to the introduction of a specific service means LTG-I (InternetLTG), which is connected to the switching network SN of the switchingsystem like every normal line/trunk group LTG 40 but comprises specificfunctions for the Internet traffic, the Internet traffic is separatedfrom the ordinary traffic and is thus controlled by separate software.As a result thereof, undesired interactions with existing features ofthe switching center can be avoided.

To this end, a great increase in the complexity of the software in theswitching center is avoided.

FIG. 2 shows the principle of the inventive method including thetemporary setup and cleardown of the payload channel connection forburst-like data transmission.

Specifically, a user of an Internet service sets up a connection the POPserver of the Internet service provider with the D-channel via theuser's terminal equipment. As a result, the ISDN B-channels are notused.

After the connection is setup and authenticated the user delivers arequest to the service provider for specific contents or services. Theavailable bandwidth of the D-channel is adequate for these tasks.

The POP of the service provider recognizes the request and edits thedata for transmission. Subsequently—controlled by the POP—, theB-channel connection to the user is set up and the requested data, forexample files or home pages, are transmitted.

After successful transmission, the B-channel connection is maintainedfor the remaining running time of the charge interval that has alreadybeen paid and is cleared down before the next charge pulse is maintainedfor the duration of a predetermined time span.

After the user has processed the requested data, for example has read arequested home page, a new request can be delivered that results in arenewed setup and cleardown of a B-channel.

For clearing down the connection to the Internet service provider, acorresponding message is sent to the POP over the D-channel and theD-channel connection is subsequently cancelled.

FIGS. 3A-3C show schematic illustrations of the call flow for anInternet session for the case illustrated in FIG. 1, namely, theconnection of the POP server (server of the Internet service provider)in the subscriber line switching center (In the illustrated call flowcase, no use of the free B-channels ensues in the transmission pauses ofthe data transmission for offering info such as, charge information;otherwise, a corresponding message would be inserted into FIG. 3.

The executive sequence of an Internet online session is explained ingreater detail below on the basis of the call flow according to FIGS.3A-3C.

First, the Internet service request made via a corresponding terminalequipment is recognized in the line/trunk group LTG and a signalingconnection, which is independent of the payload connection set up later(bearer independent), is set up via the signalling channel. TheD-channel is thereby used as what is referred to as uplink for thesignalling from the user to the switching center.

The connection setup occurs without occupying payload channels. Thefollowing advantages derive as a result thereof:

-   -   the traffic load of the switching center is limited;    -   no fixed signalling allocation is required, i.e. the message        sequence and/or the sequence of the messages is not prescribed;    -   the facility messages (of a potentially proprietary functional        protocol) can be sent in a loose sequence over the D-channel;        and    -   the switching-conditioned times, for example for entry and        authentication procedures, can be intentionally differently        charged/acquired (for example, free of charge) than the times        for the actual data transmission since there is the possibility        of handling this traffic controlled by separate software for        Internet traffic. The times of the data transmission can in turn        be charged differently than standard ISDN (“Integrated Service        Digital Network”) connections.

After the above connection, is setup, a payload channel is set up forthe connection only given data traffic, namely in downlink direction,i.e. in the direction of the subscriber. The downlink setup of thepayload channel is initiated by the POP server when the POP server isnot integrated in a switching center of the access network. Otherwise,i.e. given integration of the POP server in a switching center, thesetup is initiated by the switching center.

After the setup of a payload channel because of data traffic and aburstlike data transmission, a cleardown of the payload channelconnection ensues given maintenance of the bearer-independent signallingrelationship between the subscriber's terminal equipment and theswitching center with the POP.

The following advantages derive since the payload channels are occupiedonly given traffic volume, i.e. only temporarily:

-   -   payload channels are only briefly occupied given data traffic        that occurs burst-like (for example, Internet traffic, voice        traffic, data traffic, fax traffic, electronic data exchange        (electronic data interchange));    -   there is the possibility of utilizing the payload channels that        are free in the data transmission pauses for the implementation        of features by the switching center, potentially for the        transmission of information offered by the VST such as, for        example, charge information;    -   designational charging/acquisition of the times for making use        of the access network for the data transmission since the charge        for a payload connection is dependent on the duration in which        the required payload channels are active.

The targeted charging represents a significant competitive advantage forthe operator of the access network in an increasingly competitivesituation with price wars for customers.

The charging is usually initiated and controlled by the call control.This control can stop or, interrupt the charging given release of theB-channel or channels, and can also restart it or, let it continue torun given renewed occupation/activation of the payload channels.

It is ideally cost-saving for the ultimate consumer/subscriber when theburst-like data transmission occurs within a charge interval (i.e., hasended no later than one second before the expiration of a chargeinterval,) so that the next charge interval does not start and, thus,charge units are no longer incurred at its beginning. This can bedesignationally controlled by software, for example given integration ofthe POP in the switching center. This method is cost-saving for all feeschedules that are not based on a to-the-second billing method. Thiscost saving includes the great majority of all charging methods appliedworldwide.

A further advantage of the above-described method is the cleanseparation between times for the entry and authentication proceduresconditioned in terms of switching technology, times without B-channeloccupancy but with D-channel occupancy in an active connection as wellas times for payload channel occupations. Particularly the times for theentry and authentication procedures, can largely not be influenced bythe subscriber and should therefore not be charged to the subscribergiven proper use.

The processing of the Internet traffic by the specific line/trunk groupLTG-I allows the handling of the Internet traffic with an independentsoftware package. As a result, undesired interactions with existingfeatures of the switching center and a disproportional increase in thecomplexity of the software in the switching centers are avoided.

The configurations of the functional D-channel protocol are describedbelow. This serves to facilitate an understanding of the possibilitiesof the protocol, particularly for the realization of the invention.

The functional protocol includes a sequence of functional informationelements (FAC-IE). A functional information element, also referred tobelow as facility information element, requires a certain degree ofintelligent processing by the terminal equipment or (customer premisesequipment CPE) and the switching center to which the connection exists,namely both in generating and analyzing such information elements. Asequence of the information elements serves for the setup of theconnections, i.e. of purely signalling relationships and, potentially,payload channel connections in the method described here.

Two categories of procedures are defined for the functional signallingof supplementary services.

The first category, referred to as the “separate messages” category,uses separate message types in order to indicate a desired function. The“HOLD” and “RETRIEVE” family of messages are included in this category.

The second category, referred to as the category of “common informationelements”, uses the facility information elements FAC-IE for thesignalling of auxiliary services, but only for the signalling ofauxiliary services that do not require any synchronization of resourcesbetween user and network.

The following terms, which are defined in CCITF. “Consultative CommitteeInternational Telephony and Telegraphy”. Recommendation X.219, areemployed for specifying procedures for the control of remote operations:

remote operation

operation classes

connection-oriented transport mechanism

connectionless transport mechanism,

bearer related supplementary service procedure

bearer independent supplementary service procedure.

Remote Operation

Procedures and Components:

The remote operation protocol for handling FAC-IEs includes thefollowing procedures (means for sending and receiving messages):

INVOCATION procedure

RETURN_RESULT procedure

RETURN_ERROR procedure

REJECT procedure.

All necessary FAC-lEs for the processing of features are sent in asuitable D-channel message. The aforementioned procedures are theminimum pre-condition in order to set up and clear down connections bymeans of functional protocol.

The INVOCATION procedure is used in order to initiate an operation thatis to be implemented by the other side. An operation is a matter of apart of a supplementary service, for example a feature.

The RETURN RESULT procedure is used in order to transmit the result (onthe basis of an INVOCATION procedure) of a successfully implementedoperation.

The RETURN ERROR procedure is used in order to transmit the ERRORinformation of an unsuccessfully implemented operation.

The REJECT procedure is used in order to reject the operation requestedby the INVOCATION procedure or in order to reply.

Each of the procedures uses specific (message) components. The invoke,return result, return error and reject components are transported infacility information elements that are, in turn, sent in what arereferred to as basic call control messages or in separate FACILITYmessages between terminal equipment and switching center in order to setup or clear down signalling relationships and, potentially, payloadchannel connections.

The INVOCATION procedure thus uses the INVOKE component, the RETURNRESULT procedure uses the RETURN RESULT component, the RETURN ERRORprocedure uses the RETURN ERROR component and the REJECT procedure usesthe REJECT component.

The connection-oriented transport mechanism requires the establishmentof a data link and a transport association between the service requesterand the service provider. The mechanism allows procedures of the secondcategory to be initiated wherein success and/or failure messages arerequired. The mechanism provides a call reference within the transportassociation that represents a means for the unambiguous association ofthe transport messages of a connection.

There is no transport association given the connectionless transportmechanism; rather, only a single transport message is respectivelytransmitted, whereby a dummy value is used as call reference. Thismechanism allows the transfer of requests of operations about whoseresult no report ensues.

Supplementary Service Procedures that are Dependent on the PayloadConnection.

This type of procedure is bound to procedures for the basic call controland to a payload connection that exists, is being set up or beingcleared down. The call reference that is used by the basic call controlprocedure is adopted from the bearer connection-dependent INVOCATIONprocedures in order to correlate with the suitable transactions of thebasic call control. The allocation between the respective application onthe terminal equipment and the corresponding switching-oriented programor program status is thus achieved.

In transporting the components (dependent on the payload connection) thefollowing two categories are defined:

-   1. Point-to-point transport mechanism and;-   2. Broadcast transport mechanism.

Suitable Dchannel messages are used for the exchange of FAC-IEs. Thetransport procedures are bound to payload connections (connection setup,active phase of the connection, connection cleardown) that areidentified by the call reference.

For example, the FAC-IEs are transported in FACILITY messages for thesetup and cleardown of payload channel connections for the transmissionof data bursts.

Supplementary Service Procedures that are Independent of the PayloadConnection

This type of procedure is independent of the procedures for the basiccall control and is not correlated with a payload connection, i.e. notcorrelated with a B-channel. This procedures is ideally suited to set upa signalling relationship independent of the bearer channel and toimplement potential entry and authentication methods without occupyingan auxiliary channel, in order to occupy one or two bearer channels forthe implementation of the data transmission only given an immediatelyimpending data transmission by switching to the bearer relatedprocedure.

Transporting, of the components (independently of the payloadconnection) defines the following four categories

-   1. Point-to-point, connectionless;-   2. Broadcast, connectionless;-   3. Point-to-point connection, connection-oriented;-   4. Broadcast, connection-oriented.

The connectionless network protocol uses the “dummy” call reference. TheFAC-IE is transported in a FACILITY message.

An example of the inventive method now follows that discloses theinterworking of the bearer independent service procedure with a bearerrelated procedure.

-   a) An Internet connection that requires an authentication operation    over the D-channel starts with a bearer independent service    procedure, i.e. without B-channel occupation. This service procedure    can be connectionless (e.g. without a defied signalling procedure)    or connection-oriented;-   b) The service procedure must be switched to a bearer related    service procedure for seizing a B-channel for phases of the    burst-like data transmission or for the request/delivery of    B-channel-associated services, in that a call reference/bearer    channel reference is requested in a facility message.

FIG. 4 shows the fundamental processing of an Internet request by thesoftware of a switching center. The message sequence ensues according tothe principles explained by FIGS. 3A-3C.

The terminal equipment generate/analyze the messages of the functionalprotocol for the request of D-channel connections or for the setup ofconnections via B-channels.

Although other modifications and changes may be suggested by thoseskilled in the art, it is the intention of the inventors to embodywithin the patent warranted hereon all changes and modifications asreasonably and properly come within the scope of their contribution tothe art.

Function as Uplink:

After analysis of the functional messages (unpacking the messages) bythe functional analysis software of the LTG of the switching center, the“Internet software” assumes the evaluation of the information and theirprocessing (also, too, for the interworking with switchingcenter-specific features).

Function as Downlink:

Given cleardown of B-channel connections, the “Internet software”assumes the call control. The functional protocol translator assumes thesignalling-oriented handling of the messages.

1. A method for controlling connections in a communication network,comprising the steps of: setting up a signaling connection between asubscriber of the communication network and a service access systembased on a service connection request by the subscriber; andintermittently setting up a payload connection associated with thesignaling connection between the service access system and thesubscriber only when there is data traffic for a service and clearingdown the payload connection after the data transmission, wherein thesignaling connection and the payload connection are maintainedsimultaneously during the data transmission.
 2. The method of claim 1,wherein the service is at least one of a voice or a data service.
 3. Themethod of claim 1, further comprising the step of: charging a service bythe communication network for a time interval in which the signalingconnection and the payload connection simultaneously exist for theservice.
 4. The method of claim 3, wherein the step of clearing down thepayload connection does not occur immediately after the end of datatransmission but occurs immediately before the expiration of the timeinterval already charged.
 5. The method of claim 1, wherein theintermittently setting up of the payload connection occurs only givendata traffic.
 6. A method for controlling service connections in acommunication network in order to support access to a service via thecommunication network, comprising the steps of: initiating the setup ofa service-related signaling connection between a subscriber and aservice access system; intermittently initiating the setup of a payloadconnection between the service access system and the subscriberassociated with the signaling connection only when there is data trafficand initiating the cleardown of the payload connection after datatransmission, wherein the signaling connection and the payloadconnection are maintained simultaneously during the data transmission.7. The method of claim 6, wherein the service-related signalingconnection is to a point of presence server of an Internet serviceprovider over a D-channel.
 8. The method of claim 6, wherein the payloadconnection is a B-channel connection.
 9. The method of claim 6, furthercomprising charging for service by the service provider for each timeinterval in which the, payload connection is intermittently set up. 10.The method of claim 9, further comprising clearing down the payloadconnection after the end of data transmission and when the time intervalhas already been charged.
 11. The method of claim 6, wherein theintermittently initiating the setup of the payload connection occursonly given data traffic.
 12. The method of claim 6, wherein theintermittently initiating the setup of the payload connection occursonly given data traffic.